howerton31

2002 F150 ext cab King Ranch 4x4 5.4
I am just wondering what the pros and cons are to hollowing out my catalytic converter are. I had hollowed out mine on my ranger a few years ago because it was bad. If I hollow it out will it change gas mileage, HP, or just give up a code on my O2 sensors. I can hear some rattling coming from inside it, same thing as my ranger. Also I want a little tone to my exhaust but nothing loud. And Im being cheap and don't want to pt exhaust on. Any input will be helpful. Thanks

techrep

iTrader: (1)

It's not legal for one thing and its only a matter of time before you will have to replace it anyways...it may even through codes on you.

PirateKing

If you dont have a bender cut the back to off and leave the fronts alone. I would cut them all off before I would gut them but I like to be able to go back to stock any time. If you are comfortable with the risk your state could pass smog laws and you might have to buy four new crappy stock converters then do it.

I might be a bit too paranoid haha

JCP281

Hollowing them out is easy, take a broom handle and jam that sucker down in there. You will break up the converter pretty easy. I found that hollowed out cats gave a better sound than a true o/r midpipe(no cats) with my car. It gives you all of the deepness, without a lot of the rasp. They almost act like little mufflers.

Just be aware that you need to make sure and clean them out as best you can. If you dont your going to be replacing your muffler because a bunch of media from the cat will get stuck in there.

Its really an easy process though, shouldn't take you more than an hour or so to do. Just make sure to take your time and it will go just fine. You will throw a code though, so you can either get a tuner or make a set of these:

http://www.paladinmicro.com/MustangMILEliminator.htm

A LOT of people do this, its not an uncommon or difficult thing to do. You can buy a spare stock midpiep for $50 bucks from a lot of people.

DIABL0

if you buy 2 cats say magnaflow hiflo will it send a code?

edit: well find out i just ordered 2 hiflows off ebay 65 each free shipping

JCP281

Generally it doesnt. As long as you have some cats it wont throw a code. How many cats are on the stock midpipe for these trucks? Is it 4 or 2?

TYRANDOLPH333

i deleted my two rear cats and didnt throw a code. so i think it all just depends on the truck

Cain64

these trucks have 4 cats, 1 on each down pipe on headers(2) then about 6-12 inches from there, there is another pair, one on each pipe then the pipes join to go to the muffler. I have read up but i have not done it myself, you can remove completely the 2 rear ones and be fine with emissions. Not sure what you do with the o2 sensors or wires though

kaldous4421

Has anyone went straight pipes out the back off the cats instead of the pipes joining then y-ing again to create the dual pipes?

TYRANDOLPH333

i didnt do anything to my o2 sensors cuz it didnt throw a code. and if it does there is easy fixes